Your mission in this online defense game is to defend a critical research base from your bunker during an alien invasion. Go to Construction screen between waves to upgrade your buildings and weapons. All humanity is counting on you to beat back the alien hordes while you build up your base and research alien technology in a quest to find a weapon capable of defeating the alien menace once and for all. Use YOUR MOUSE to aim and shoot. Use 0-9 NUMBER KEYS to select weapon (or use "Q" KEY to go through weapons). Press "A" KEY to fire artillery. Good luck!